2002 SLT+ 5.9 engine. What is the best oil to use? I have always used Valvoline in all of my other vehicles. Do you recommend synthetic or regular oil and what is the advantage of synthetic? Thank you.

 

Synth all the way. It doesn't break down nearly as easily and it is pretty much up to you what brand you use but do go with 10w30 unless you live in subzero temps. A lot of guys use Mobil 1 and royal purple. I personally started on q-state.

 

I know it costs more, but can you wait longer inbetween oil changes and are the myths about seals leaking after changing types true?

 

The myths are only true on engines that are built up with "Sludge".The sludge prevents the engineswith worn out seals from leaking and when you use a synthetic oil it breaks down the sludge,this would cause a leak if the seals are bad.And as far as the brand goes; Valvoline Durablend, Royal Purple, and Mobil 1 are good brands to use. They even have synthetic oils that are specially designed for high mileage engines. They are also alot cheaper if you goto somwhere like Wal-mart to get them!

 

If your seals leak they are going to leak. Synthetic's if full and not blended, you can go about 5000-7500 miles between changes. You need to get a good miron filteration filter to run this. 5000 if towing or wheeling and stop and go. 7500 if Hwy miles.

Wal-Mart sells Mobil 1 Fully Synthetic for $22 for a 5 quart bottle and you can get a Fram Tough Gard filter for $5. This is the combo I like to use but there are others. I think Mobil 1 has the best oil because of expereance but there are others. Just make sure that what you buy is Fully Synthetic

 

TRMB:
As said here, Mobil 1, Royal Purple, and others are all good choices. Think about what your driving style is, and then pick based upon that.

I will also assume that you are not under any type of extended warranty which requires that you follow the owners manual to a T.
If you drive more than 3k miles a month, synthetic is going to be significantly more expensive to run, however you can run it for 5-7k with a good filter in mostly hwy driving. If most of your driving time is short, stop and go, or you do alot of towing you will want to stick closer to the 3-4k interval.

With the technology these days, OC intervals are going up for many vehicles. GM, MB, andBMW are all equipped with some type of oil life monitor that will tell you when to make the service. The MB systems say they might go as high as 15k depending on driving style and using synthetic oil of course.

I do ours here on a 3k /4mo interval as we make alot of short trips, but we also run Mobil 1.

Don

 

highly recommend a full synthetic oil...IMHO...the absolute best you can go with would be AMSOIL hp with an amsoil filter...amsoil is rated at 15,000 severe service or 25,000 normal service. i run amsoil and usually go around 10,000, and the filter is high capacity so you don't need to replace it every few thousand. My second choice would be a Mobil 1 oil and Mobil 1 filter, also very good and very close in comparison to amsoil. Valvoline Synpower (not durablend) is also a good full synthetic. I would definately not recommend any Fram filters, nor quaker state, castrol, or pennzoil synthetics. Castrol makes a very good conventional, but there synthetic is a group III vs. a group V ams or mobil 1, it doesn't compare, and for about the same price, why not choose the better performing oil? and if you have significant mileage i would run a fast motor flush just before switching to synthetic to remove sludge and other excess buildup.

 

I don't see how you can drive 15000-25000 miles on a oil change. First of all the oil base is not bad. Synthetics last longer because the molecules are broken down to only two. The problem is that the federal laws mandate that refineries can call a oil Full Synthetic if they process it to two molecules or refine it for so many hours. Problem is just because you refine it for a length of time doesn’t mean that it is Fully Synthetic. This is a loop hole in the federal mandate laws. I know for a fact that Mobil 1 is fully broke down. I can't tell you what the other companies do but they don't have the capita to research as much as the biggest oil company in the world does bottom line. Fram isn't the best filter out there but it is not that bad. Each to their own. Just make sure you have a good micron filter backed by good materials.\
Now let's get this 15000-25000 oil change out of the way. These findings are bull ****. What where their findings based on. Come on now. Oil base is the same. Now if you break it down to a true Full Synthetic this is a lot better to work with. But you still have the additives that make oil different weights. Gear lube and SAE 10-30 are the same oil base just different additives. You motors use these additives to properly lubricate their motors. As you drive the soot, break down particles, and worn out additives darken your oil. This is why it darkens. Oil filters take out the harmful particles but the worn out additives slip through and don't lubricate your engine properly. This is why you need to change out your filter. It removes the particles. Now you change out your oil to remove the worn out additives and replenish the additives. What part of this do people not see. There is no way an oil can go this long bottom line!

 

I agree.

 

as far as the filter goes...crack open a fram and a mobil 1 and compare the two...tell me the mobil won't last twice as long. And the 15k oil change interval, welll it comes STRAIGHT from the amsoil web site. check it out bud http://www.amsoil.com/storefront/asl.aspx so don't argue with me, argue with amsoil. Mobil 1 'extended performance' also has asuggested interval of 15k on their web site. Just because you're not comfortable with going 15k without an oil change, doesn't mean that oil will fully break down in that time. And yes Mobil 1 is a full synthetic. Amsoil is a PURE synthetic.